"The planes were flying at an altitude of 7,000 meters [23,000 feet] and were downed by our air defense system," Ruslan Kishmariya said.

Abkhazia's defense minister, Merab Kishmariya, confirmed that two planes had been shot down. He previously said that only one drone had been downed.

"Considering the altitude of the aircraft, their fragments will be scattered within a radius of between eight and 12 kilometers [5-7 miles]," the presidential envoy said, adding that a group of experts was already working at the crash site of the first drone and a search was underway for the crash site of the second.

The Georgian Foreign Ministry called Abkhazia's claims "absurd," and said they were aimed at escalating tensions in the region.

The breakaway republic also claimed on Sunday that Georgia had deployed almost 7,500 troops on its border with Abkhazia. The breakaway republic's defense minister said the troops were on a state of alert, adding that Abkhazia had also put its troops on standby.

Sergei Shamba, the foreign minister of Abkhazia, said the troops in the republic were put on an alert on order from President Sergei Bagapsh, but it did not mean that the unrecognized republic was preparing for a war.

"Putting army on high alert is just a first stage, but it does not mean that we [Abkhazia] have begun full-scale preparations for a war," Shamba said.

Russia's Foreign Ministry said in a statement later on Sunday that Georgia will be responsible for raising tensions in the conflict-stricken region as it again sent in its surveillance drones to Abkhazia.

"By resorting to the adventurism of sending in surveillance drones and stepping up military preparations in the conflict zones, Tbilisi has knowingly embarked upon the path of raising tensions in the region," the ministry said. "The responsibility for the consequences of such a course lies with Georgia."

Abkhazia, alongside another Georgian breakaway republic, South Ossetia, broke away from Georgia in the early 1990s following the collapse of the Soviet Union. Between 10,000 and 30,000 people were killed in the Georgian-Abkhazian conflict and some 3,000 in Georgian-South Ossetian hostilities. Georgia is looking to regain control over the two de facto independent republics.

Tensions between Moscow and Tbilisi have been escalating rapidly since Russia's outgoing President Vladimir Putin called for closer ties between Moscow and the two breakaway republics in mid-April.

Tbilisi also accused Russia of shooting down its drone on April 20 - a claim Russia flatly denied, calling Georgia's video footage fake.